JP6678553B2 - Electronic device and touch panel - Google Patents

Description

  The present invention relates to an electronic device having a wiring pattern formed by printing, and more particularly to a touch panel.

  In recent years, printing methods that are excellent in productivity and advantageous in terms of manufacturing cost have been used for forming electrode patterns and wiring patterns of various electronic devices such as touch panels, touch sensors, membrane switches, and organic ELs. . Above all, gravure offset printing has attracted attention as being suitable for forming high-definition patterns.

  Patent Literature 1 describes that a touch sensor is formed by gravure offset printing as described above. FIGS. 8 and 9 illustrate a configuration of a touch key including a touch sensor and a touch sensor described in Patent Literature 1. 1 shows a gravure offset printing machine used in the manufacture of a gravure printing machine.

  As shown in FIG. 8, the touch key includes a touch sensor 10 and a touch sensor drive circuit 15. The touch sensor 10 connects a substrate 11, a plurality of mesh electrodes 12 formed on the substrate 11, an outer edge wiring 13 provided on an outer edge of the mesh electrode 12, and the outer edge wiring 13 and the touch sensor drive circuit 15. Connection wiring 14. The mesh electrode 12 has a mesh shape, and the outer edge wiring 13 is formed so as to extend along the upper side of the mesh electrode 12 in FIG.

  The mesh electrodes 12, the outer edge wirings 13 and the connection wirings 14 are formed on the substrate 11 at the same time by using a gravure offset printing machine and then cured.

  As shown in FIG. 9, the gravure offset printing machine 20 includes a plate table 21, a base table 22, a doctor blade 23, a transfer roller 24, a device frame 25, and a dispenser (not shown). I have. An intaglio (gravure plate) in which the plate table 21 is formed with a concave pattern 26 having a mesh-shaped concave portion 26a, an outer-edge concave portion 26b, and a connection concave portion 26c corresponding to the mesh-like electrode 12, the outer edge wiring 13, and the connection wiring 14 of the touch sensor 10, respectively. ) 27 is mounted and fixed, and the substrate 11 which is a printing medium is mounted and fixed on the base material table 22. The doctor blade 23 and the transfer roller 24 are movable along the X axis and the Z axis, and the dispenser is also movable along the X axis and the Z axis.

  The doctor blade 23 is slid along the X axis on the intaglio 27 while the conductive paste 28 is supplied onto the intaglio 27 by the dispenser, so that the conductive paste 28 is filled in the concave pattern 26 of the intaglio 27. . The conductive paste 28 filled in the concave pattern 26 is received by the transfer roller 24, and the print pattern held by the transfer roller 24 is transferred to the substrate 11. By heating and curing the print pattern transferred to the substrate 11, the mesh electrode 12, the outer edge wiring 13, and the connection wiring 14 of the touch sensor 10 are completed.

JP 2015-45890 A

  As described above, Patent Document 1 describes that a wiring pattern of a touch sensor is formed by gravure offset printing. However, in the wiring pattern as shown in FIG. The wiring element which mediates the connection between the connection wiring 12 and the connection wiring 14 is a linear outer wiring 13, and the outer edge recess 26 b of the intaglio 27 corresponding to the outer wiring 13 is parallel to the doctor blade 23 as shown in FIG. Therefore, in the process of squeezing, there may occur a problem that the doctor blade 23 falls into the outer edge concave portion 26b and scrapes out the conductive paste (conductive ink).

  Therefore, in order to avoid such a problem, a wiring element that mediates the connection between the mesh electrode 12 and the connection wiring 14 is not provided by the linear outer edge wiring 13 but by the edge (upper side) of the mesh electrode 12. A pad made of a thin line mesh composed of a line segment oblique to the line direction, that is, a line segment oblique to the extension direction of the doctor blade 23, and the connection wiring 14 is further extended in parallel with the extension direction of the doctor blade 23. A configuration is considered in which a portion having a dotted line is a wavy line.

  Based on the above idea, a sensor electrode array arranged in the sensor region, a lead line for external connection provided in a frame surrounding the sensor region, and a pad that mediates the connection between the sensor electrode line and the lead line In a touch panel having a wiring pattern including: a sensor electrode row is composed of a first fine line mesh, a pad is composed of a second fine line mesh having a higher density than the first fine line mesh, and When the wiring pattern was formed using gravure offset printing, with the part extending parallel to the blade extending direction as a wavy line, the problem of ink scraping due to the dropping of the doctor blade into the concave part of the gravure plate was resolved, Over the entire display area (sensor area) of the touch panel, print shading that can be visually recognized according to the position of the pad occurs We have found a new problem.

  More specifically, the sensor electrode array is relatively dense in the downstream region in the squeezing direction of the portion where the pad is located, and relatively light in the downstream region in the squeezing direction of the portion between the pads where the pad is not located. Is printed.

  An object of the present invention is to provide an electronic device and a touch panel in which such visible shading of light and shade is not generated.

  According to the first aspect of the present invention, an electrode composed of a cured conductive ink film, composed of a first thin wire mesh, a lead wire, and a second fine wire mesh is used to connect the electrode and the lead wire. A plurality of wiring patterns including intervening pads are arranged and provided on the surface of the base material, all the pads are arranged along one direction on the surface, and all of the pads are arranged on one side sandwiching the arrangement of the pads. In the electronic device in which the electrodes are located and all the lead lines are located on the other side, the distance between adjacent pads in the one direction is all 100 μm or less.

  According to a second aspect of the present invention, in the first aspect of the present invention, all the electrodes have linear edges parallel to the one direction, and all pads are extended along the edges and connected to the electrodes. And a protruding portion protruding from the straight portion to the other side and connected to the lead wire, and all the straight portions are aligned on a straight line extending in the one direction.

  In the invention of claim 3, in the invention of claim 1 or 2, the first fine line mesh and the second fine line mesh are constituted by line segments obliquely in both the one direction and the direction perpendicular to the one direction, The lead line has a shape of a wavy line extending in the one direction.

  According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, the second fine line mesh has a higher density than the first fine line mesh.

  According to the fifth aspect of the present invention, the sensor electrode array composed of the first fine wire mesh and arranged in the rectangular sensor area, the lead wire provided in the frame surrounding the sensor area, and the second fine wire mesh In a touch panel composed of a conductive ink film having a cured wiring pattern including a sensor electrode array and a pad that mediates the connection of the lead wire, the pads are arranged along the rectangular side, and the pad is arranged on the rectangular side. Among the pads arranged along, all pads located on at least one side have an interval between adjacent pads of 100 μm or less.

  According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the first fine line mesh and the second fine line mesh are constituted by line segments obliquely intersecting the sides of the rectangle. The shape of the portion extending in parallel to the arrangement direction of the pads, all of which are 100 μm or less, is taken as a wavy line.

  According to a seventh aspect of the present invention, in the fifth or sixth aspect, the second fine line mesh has a higher density than the first fine line mesh.

  According to the present invention, it is possible to obtain an electronic device and a touch panel that do not generate visible stripes of light and shade stripes, and to provide an electronic device and a touch panel that have an excellent display portion and have a good appearance in that respect. Can be.

FIG. 3 is a diagram for describing a configuration outline of a touch panel. FIG. 2 is a partially enlarged view showing details of a first sensor electrode row, a pad, and a lead line of the touch panel shown in FIG. 1. FIG. 2 is a partially enlarged view showing details of a second sensor electrode row of the touch panel shown in FIG. 1. FIG. 2 is a partially enlarged view showing details of a leader line of the touch panel shown in FIG. 1. FIG. 1 is a partially enlarged view showing details of a main part of an embodiment of a touch panel according to the present invention. A is a diagram illustrating a wavy wiring pattern, and B is a diagram illustrating tailing and bleeding of conductive ink. 7A is a diagram illustrating a configuration example of a gravure plate corresponding to a wavy wiring pattern, and FIG. 6B is a diagram illustrating another configuration example of a gravure plate corresponding to a wavy wiring pattern. The figure which shows the conventional structural example of a touch sensor. The figure which shows the gravure offset printing machine used for manufacture of the touch sensor shown in FIG.

  First, a description will be given of a configuration of a capacitance-type touch panel that has triggered the discovery of a new problem that printing unevenness in density that can be visually recognized occurs in accordance with the position of a pad.

  FIG. 1 shows a schematic configuration of a capacitive touch panel. In FIG. 1, reference numeral 30 denotes a transparent substrate. The capacitive touch panel has a configuration in which, for example, a first conductor layer, an insulating layer, a second conductor layer, and a protective film are sequentially laminated on a transparent substrate 30.

  Although the sensor electrode row is not shown in detail in FIG. 1, the sensor electrode row includes a plurality of first sensor electrode rows and a plurality of second sensor electrode rows, and the plurality of first sensor electrode rows are the first conductor And a plurality of second sensor electrode rows formed by a second conductor layer insulated from the first conductor layer by an insulating layer. In FIG. 1, a portion surrounded by a rectangular frame indicates a sensor region 40 in which a sensor electrode row is located. The outside of the rectangular frame forms a frame portion 50 surrounding the sensor region 40.

  FIG. 2 shows details of a first sensor electrode row 61, a dummy electrode 62, a lead wire 63, and a pad 64 formed by a first conductor layer, and FIG. 3 shows a structure formed by a second conductor layer. 2 shows details of a second sensor electrode row 71 and a dummy electrode 72 shown in FIG. 2 and 3 show the upper left portion of the sensor region 40 in FIG.

  In the sensor region 40, a dummy electrode 62 is formed together with the first sensor electrode row 61 as shown in FIG. 2, and a dummy electrode 72 is formed together with the second sensor electrode row 71 as shown in FIG. I have. The dummy electrodes 62 and 72 are formed so as to make the first sensor electrode row 61 and the second sensor electrode row 71 inconspicuous, respectively.

  The first sensor electrode row 61, the dummy electrode 62, the second sensor electrode row 71, and the dummy electrode 72 have the same specification of a thin mesh (first mesh) formed by line segments obliquely intersecting the sides of the rectangular sensor region 40. A first sensor electrode row 61 insulated from the dummy electrode 62 and a second sensor electrode row 71 insulated from the dummy electrode 72 are respectively formed by dividing a predetermined portion of the thin wire mesh. ing. In this example, the unit lattice of the first fine line mesh is a rhombus with a side length of 400 μm, and the line width of the fine lines constituting the mesh is 7 μm. The first sensor electrode row 61 and the dummy electrode 62 and the second sensor electrode 71 and the dummy electrode 72 are separated and insulated at intervals of about 20 μm.

  The first sensor electrode row 61 includes a plurality of island-shaped electrodes 61a arranged in the X direction parallel to the long sides 41 of the rectangular sensor region 40, and a connecting portion 61b connecting the adjacent island-shaped electrodes 61a. . A plurality of first sensor electrode rows 61 are provided in parallel in the Y direction parallel to the short sides 42 of the rectangular sensor area 40. The second sensor electrode row 71 includes a plurality of island-shaped electrodes 71a arranged in the Y direction and a connecting portion 71b for connecting the adjacent island-shaped electrodes 71a. A plurality of second sensor electrode rows 71 are provided in parallel in the X direction.

  The first sensor electrode row 61 and the second sensor electrode row 71 cross each other while being insulated from each other. At this time, the first sensor electrode row 61 and the second sensor electrode row 71 are overlapped so as to intersect each other at a midpoint where the rhombic side of the unit cell is divided into 200 μm at a time, that is, the first conductor When the first sensor electrode row 61 and the dummy electrode 62 of the layer and the second sensor electrode row 71 and the dummy electrode 72 of the second conductor layer are correctly (no error) overlapped, the length of one side is 200 μm. Are uniformly formed in the sensor region 40. Note that the connecting portions 61b and 71b are located at positions overlapping each other.

  As shown in FIG. 1, lead lines 63 and 73, terminals 81, and ground wiring 82 are formed in the frame portion 50. Pads are formed in FIG. 1, although not shown in FIG. Lead lines 63 are drawn from both ends in the X direction of each first sensor electrode row 61 via pads 64 (see FIG. 2), and lead lines 73 are drawn from one end of each second sensor electrode row 71 in the Y direction. Each is pulled out via a pad. In FIG. 1, only a plurality of lead lines 63 and 73 provided on the frame portion 50 are arranged at both ends of the arrangement, and those other than those located at both ends are omitted.

  The terminals 81 are arranged and formed at the center of one long side of the rectangular transparent substrate 30, and the lead wires 63 and 73 extend to the terminals 81 and are connected to the terminals 81. The ground wiring 82 is formed on the periphery of the frame 50 so as to surround the lead lines 63 and 73. The ground wiring 82 is also connected to the terminal 81.

  Similarly to the lead 63, the lead 73 and the terminal 81 are formed by the first conductor layer, and the ground wiring 82 is formed by both the first and second conductor layers.

  The pad 64 that mediates the connection between the first sensor electrode row 61 and the lead-out line 63 and the pad that mediates the connection between the second sensor electrode row 71 and the lead-out line 73 (not shown) are both long in the sensor region 40. It is composed of a thin line mesh (second thin line mesh) composed of line segments obliquely intersecting the side 41 and the short side 42, and the second thin line mesh is a first line forming the first and second sensor electrode rows 61 and 71. The density is higher than that of one fine wire mesh. In this example, the unit lattice of the second fine line mesh is a square having a side length of about 40 μm, and the line width of the fine lines constituting the mesh is 10 μm.

  The terminal 81 and the ground wiring 82 are not shown in detail, but are formed of a finer wire mesh having a higher density than the first fine wire mesh forming the first and second sensor electrode arrays 61 and 71, similarly to the pad 64. Have been.

  On the other hand, the lead lines 63 and 73 are not meshes but linear wirings. In this example, the lead lines 63 are drawn from the pads 64 and are parallel to the short sides 42 of the sensor area 40, that is, in the Y direction. The long stretched portion is constituted by a wavy line as shown in FIG. FIG. 4 shows a portion where a large number of leader lines 63 arranged in the lower left part of the frame portion 50 in FIG. 1 change the extending direction from the Y direction to the X direction.

  The first and second conductor layers having the above configuration are formed by gravure offset printing using a conductive ink containing conductive particles such as silver. The squeezing direction S of the doctor blade with respect to the gravure plate defining the wiring pattern of the conductor layer is set in the X direction parallel to the long side 41 of the sensor region 40 as indicated by an arrow in FIG.

  In this example, as described above, the wiring pattern other than the lead lines 63 and 73 is formed by a thin line mesh composed of line segments oblique to the squeezing direction S of the doctor blade. Since the portion of the line 63 that extends long in the Y direction (extending direction of the blade edge of the doctor blade) is formed by a wavy line, the doctor blade falls into the concave portion of the gravure plate defining these wiring patterns and scrapes out the conductive ink. This makes it possible to eliminate the occurrence of inconveniences.

  On the other hand, in the touch panel having such a configuration, as described above, in the downstream basin in the squeezing direction S of the site where the pad 64 is located, the squeezing is performed in the gap between the pads 64 where the pad 64 is not located. In the downstream region in the direction S, a relatively thin, fine line mesh in the sensor region 40 is printed, and a phenomenon occurs in which visible stripe-like uneven printing of light and shade occurs.

  It has been found that this printing unevenness appears remarkably as the number of printings is increased with the same gravure offset printing apparatus, and the difference in shading is emphasized.

  The present inventors have found that the cutting edge of the doctor blade repeatedly slides on the concave portion of the gravure plate corresponding to the pad 64 made of a high-density thin wire mesh, thereby causing partial abrasion of the blade edge, resulting in abrasion. Supposed that the deterioration of the squeezing ability (scraping ability) caused by the printing is the cause of the printing unevenness, and created a solution for setting the interval between the pads to a size smaller than the resolution that can be visually recognized by humans. In addition, an effect of eliminating printing unevenness was obtained.

  FIG. 5 shows the details of the main part of an embodiment of the touch panel according to the present invention which has obtained the effect of eliminating the printing unevenness. FIG. 5 corresponds to FIG. 2 described above.

  Pads 64 ′ formed by the second fine wire mesh and arranged in the Y direction along the short sides 42 of the rectangular sensor region 40 are linear pads parallel to the Y direction of the first sensor electrode row 61. A straight portion 65 extending along the edge and connected to the first sensor electrode row 61; and a projecting portion 66 protruding from the straight portion 65 toward the outer edge of the frame portion 50 and connecting to the lead wire 63. And The linear portions 65 of all the pads 64 'are aligned on a straight line, and in this example, the distances d between adjacent pads of the pads 64' arranged in this manner are all 100 μm or less. In addition, the pad located on the other end side of the first sensor electrode row 61 also has an adjacent pad interval d of 100 μm or less. By setting the distance d between the pads in this way, the printing unevenness of the light and shade stripes which can be visually recognized was eliminated.

  Here, the grounds for setting the upper limit of the inter-pad distance d to 100 μm will be described.

  As described above, when the fine wire mesh of the first conductive layer and the fine wire mesh of the second conductive layer are correctly overlapped (without error), a rhombic lattice having a side length of 200 μm is formed in the sensor region 40. That is, it is formed uniformly on the display unit. In this state, nothing can be visually recognized by the naked eye, that is, the fine lines constituting the fine line mesh cannot be visually recognized.

  However, if the first conductor layer and the second conductor layer are misaligned and the rhombic intersection is performed at a position deviated to any point from the midpoint of the side, a set of close thin lines However, there is a problem that a relatively dark line that can be visually recognized is drawn like a single thick line.

  For this reason, the permissible range of misalignment of the first conductor layer and the second conductor layer is set to 50 μm for strict specifications and 100 μm for loose specifications. In other words, it is required that the fine wires constituting the fine wire mesh be separated by 150 μm or more in a strict specification, and 100 μm or more in a loose specification.

  Therefore, in this embodiment, the upper limit of the distance d between the pads is set to 100 μm based on the above loose specifications. If the distance d between the pads is set to 100 μm or less, the width of the light portion of the printing unevenness in the form of dark and light stripes is lower than the visual resolution, so that the light portion is not recognized, that is, the printing unevenness is not recognized.

  In addition, as a more preferable embodiment for improving the appearance of the display unit, a manufacturing condition in which the upper limit of the inter-pad distance d is set to 50 μm can be adopted so as to surely lower the resolution of visual recognition.

  Furthermore, in order to eliminate the visibility of the printing unevenness, as the most preferred embodiment, a manufacturing condition in which the upper limit of the inter-pad interval d is 10 μm can be adopted based on the interval for securing insulation.

  The narrowing of the inter-pad distance d is required when the pad is made of a high-density fine wire mesh and a plurality of pads are arranged in the extending direction of the blade edge of the doctor blade. At this point, if a pad meeting this condition is present only on one side of the rectangular sensor area 40, the inter-pad distance d of the pad located on that side is reduced. In the lead line, the shape of a portion extending in parallel to the arrangement direction of the pads arranged with the inter-pad interval d narrowed is a wavy line.

  FIG. 6A shows a dashed line shape applied to a wiring pattern, and a dashed wiring pattern 90 is formed by a triangular wave.

  When the wavy line of the wiring pattern forming the wavy line is a triangular wave as shown in FIG. 6A, the printed wiring pattern 90 is likely to have a shape defect as shown in FIG. 6B. That is, tailing of the conductive ink with a may occur from the folded portion (corner) of the triangular wave located on the downstream side with respect to the squeezing direction S, and bleeding of the conductive ink with b may cause the folded portion of the triangular wave. May occur.

  In order to prevent such tailing a and bleeding b, as shown in FIG. 7A, a convex portion 102 is formed in the concave portion 101 of the gravure plate 100 corresponding to the wavy wiring pattern 90 to reduce the amount of the conductive ink. It is effective to do. As a result, voids (spaces without a film) or dents corresponding to the convex portions 102 of the gravure plate 100 are formed in the wiring pattern 90 of the wavy line. The convex portion 102 is preferably formed so as to be located at the folded portion of the wavy line, and is further preferably formed so as to be shifted in the squeezing direction S as shown in FIG. 7B.

  In addition, since the line-shaped lead lines 63 and 73 of the touch panel are formed by wiring thicker than the fine lines constituting the fine line mesh in order to suppress the resistance value and to avoid the risk of disconnection, they are formed on the blanket in the gravure offset printing. Printing defects due to the remaining conductive ink on the surface are likely to occur. Forming the convex portion 102 in the concave portion 101 of the gravure plate 100 is also preferable in preventing such a printing failure. In this respect, it is preferable to form a convex portion not only at the wavy portion of the wiring pattern but also at the concave portion of the gravure plate corresponding to the portion on the straight line.

  As described above, the touch panel according to the present invention has been described. However, the present invention is not limited to the touch panel, and also covers an electronic device such as a touch sensor as shown in FIG. 8 as a conventional example.

  That is, it includes an electrode made of a cured conductive ink film and composed of a first fine wire mesh, a lead wire, and a pad composed of a second fine wire mesh and mediating the connection between the electrode and the lead wire. A plurality of wiring patterns are arranged on the surface of the base material, all the pads are arranged along one direction on the surface of the base material, and all the electrodes are located on one side sandwiching the arrangement of the pads. An electronic device in which all the lead lines are located on the other side is a target. In such an electronic device, the intervals between adjacent pads arranged in one direction are all 100 μm or less.

DESCRIPTION OF SYMBOLS 10 Touch sensor 11 Substrate 12 Reticulated electrode 13 Outer edge wiring 14 Connection wiring 15 Touch sensor drive circuit 20 Gravure offset printing machine 21 Plate table 22 Substrate table 23 Doctor blade 24 Transfer roller 25 Device frame 26 Depressed pattern 26a Reticulated recess 26b Recess 26c Connection recess 27 Intaglio 28 Conductive paste 30 Transparent substrate 40 Sensor region 41 Long side 42 Short side 50 Frame 61 First sensor electrode row 61a Island electrode 61b Connecting part 62 Dummy electrode 63 Leading lines 64, 64 'Pad 65 Linear part 66 Projection part 71 Second sensor electrode row 71a Island electrode 71b Connection part 72 Dummy electrode 73 Lead wire 81 Terminal 82 Ground wiring 90 Wiring pattern 100 Gravure plate 101 Depression 102 Convex

Claims (7)

An electrode made of a cured conductive ink film, composed of a first fine wire mesh, a lead wire, and a pad composed of a second fine wire mesh and mediating the connection between the electrode and the lead wire. A plurality of wiring patterns are arranged on the surface of the substrate, and all the pads are arranged along one direction on the surface, and all the electrodes are located on one side of the pad. An electronic device in which all said leads are located on the other side,
An electronic device, wherein the intervals between the pads adjacent in the one direction are all 100 μm or less. The electronic device according to claim 1,
All the electrodes have straight edges parallel to the one direction,
All the pads include a linear portion extending along the edge and connected to the electrode, and a protruding portion protruding from the linear portion to the other side and connected to the lead line,
An electronic device, wherein all the straight portions are aligned on a straight line extending in the one direction. The electronic device according to claim 1 or 2,
The first fine line mesh and the second fine line mesh are configured by line segments oblique to both the one direction and a direction orthogonal to the one direction,
The electronic device, wherein the lead wire has a shape of a wavy line extending in the one direction. The electronic device according to any one of claims 1 to 3,
The electronic device according to claim 1, wherein the second fine wire mesh has a higher density than the first fine wire mesh. A sensor electrode array formed of a first thin wire mesh and arranged in a rectangular sensor region, a lead wire provided in a frame surrounding the sensor region, and a second thin wire mesh formed of the sensor electrode array A wiring panel including a pad that mediates the connection of the lead wire and a wiring pattern, the touch panel including a cured conductive ink film,
The pads are arranged along the sides of the rectangle,
The touch panel, wherein, among the pads arranged along the sides of the rectangle, all of the pads located on at least one side have an interval between adjacent pads of 100 μm or less. The touch panel according to claim 5,
The first fine line mesh and the second fine line mesh are constituted by line segments obliquely intersecting the sides of the rectangle,
A touch panel, wherein a shape of a part of the lead line extending in parallel to a direction in which the pads are arranged so that an interval between adjacent pads is 100 μm or less is a wavy line. The touch panel according to claim 5, wherein
The touch panel according to claim 1, wherein the second fine line mesh has a higher density than the first fine line mesh.